Gender disparities in high-quality research revealed by Nature Index journals

Abstract

Background: The present study aims to elucidate the state of gender equality in high-quality research by analyzing the representation of female authorships in the last decade (from 2008 to 2016).

Methods: Based on the Gendermetrics platform, 293,557 research articles from 54 journals listed in the Nature Index were considered covering the categories Life Science, Multidisciplinary, Earth & Environmental and Chemistry. The core method was the combined analysis of the proportion of female authorships and the female-to-male odds ratio for first, co- and last authorships. The distribution of prestigious authorships was measured by the Prestige Index.

Results: 29.8% of all authorships and 33.1% of the first, 31.8% of the co- and 18.1% of the last authorships were held by women. The corresponding female-to-male odds ratio is 1.19 (CI: 1.18-1.20) for first, 1.35 (CI: 1.34-1.36) for co- and 0.47 (CI: 0.46-0.48) for last authorships. Women are underrepresented at prestigious authorships compared to men (Prestige Index = -0.42). The underrepresentation accentuates in highly competitive articles attracting the highest citation rates, namely, articles with many authors and articles that were published in highest-impact journals. More specifically, a large negative correlation between the 5-Year-Impact-Factor of a journal and the female representation at prestigious authorships was revealed (r(52) = -.63, P < .001). Women publish fewer articles compared to men (39.0% female authors are responsible for 29.8% of all authorships) and are underrepresented at productivity levels of more than 2 articles per author. Articles with female key authors are less frequently cited than articles with male key authors. The gender-specific differences in citation rates increase the more authors contribute to an article. Distinct differences at the journal, journal category, continent and country level were revealed. The prognosis for the next decades forecast a very slow harmonization of authorships odds between the two genders.

Fig 1. Time trend of female authorships on the global level.

(A) The relative frequency of female authorships (FAP, bottom), the pattern of FAORs (with FAOR-triplet, top) and its associated Prestige Index (PI) are depicted by year and averaged over time. The very time-stable and unbalanced FAOR distribution is constantly characterized by the FAOR-pattern (+, +, -). The significantly negative PI points to a lack of prestigious authorships held by women. (B) The FAP exhibits a marginal increase as documented by its average annual growth rate (AAGR) of 0.7% per year with the highest rate for last authorships (1.5%).

Fig 2. Female authorships by journal category.

(A) The subject category Earth & Environmental has much favorable authorship odds for women than other categories. The number of considered male and female authorships is given in brackets. (B) In all categories, the FAP exhibits a positive annual growth with a relatively higher growth for first and last authorships and a relatively lower growth for co-authorships.

Fig 3. Correlation of journal parameters.

(A) There is no correlation between the 5-Year-Impact-Factor of a journal and its FAP. (B) A large negative correlation between the 5-Year-Impact-Factor of a journal and its Prestige Index was revealed. (C) The graph shows a small, but not significant negative correlation between the FAP and the Prestige Index of a journal.

Fig 4. Female authorships by authors per article.

The more authors contribute to an article, the higher is the FAP and the lower is the representation of women at prestigious authorships.

Fig 5. Gender-specificity of citations & scholarly productivity.

(A) The descendingly ordered citation rates shows that articles with male key authorships are more frequently cited than articles with female key authorships. The mean citation rate of 37.5 citations/article is depicted by a dotted line (Kruskal-Wallis test, (*): p < .05 (**): p < .01). (B) Average citation rates of both, ungrouped articles (bars) and articles that were grouped by the gender of their key authorships (lines), plotted as a function of the number of authors. Statistically, the citation rate of an article is higher the more authors are involved. The differences in citation rates between the two genders increase with the number of authors per article. (C) Gender-specific distribution of the number of articles per author. Women dominate the sub-groups 'author has 1 or 2 article(s)'. All other sub-groups are characterized by a relatively over-representation of male authors. This finding correlates with the higher productivity of male authors, as 61.0% male authors are responsible for 70.2% of all authorships.

Fig 6. Linear projection of the development of female authorships on the global level.

The prognosis for the next decades forecasts a slow harmonization of authorship odds between the two genders and the persistence of the unfavorable FAOR-pattern with a negative Prestige Index. A FAP of 33.1% is prognosticated for the year 2025.